The Official SCP Foundation Xmas thread is here. Mostly full of people being nice to each other (including me), but you never know, it might not last.

No one's yet posted any winter holiday related tales or SCPs this actual winter holiday, so I've dug up a few that are related:

SCP-2412-J, the Laplander. A joke article. Bit of a cheesy joke, but it's a classic article. (From 2008, the year the site was created. That makes everything better.)

Christmas is a collection of holiday-themed creepypasta from a year ago. No understanding of the SCP Foundation is required to read.

Silberescher's On the Seventh Day of Christmas, a story about SCP-1802, "Skip". A word of warning: "Skip" is a riff on the core concept of the site itself, so you may not want to make it the first article you read. Or, hey, maybe that's a plus.

Sophia Light's Joy to the World is another meta-themed story, though the point of this one is in itself a joke. Definitely a fun read if you know what the SCPs mentioned are, or are willing to look them up. (One tidbit: SCP-504 are tomatoes that fling themselves at you if you make a bad joke. Somewhat central to the story.)

And, finally, Smapti's How Dr. Clef Saved Christmas is another story full of in-jokes. Goddammit, I didn't realize when I first started gathering these links about how self-referential we all are. Maybe I ought to have considered that in advance! Much too late now, though.

On that note, if you don't know what the SCP Foundation is, and you're interested, and you like creepy/horror-themed stuff with the occasional bout of hilarity or over-the-top action,
start with the list of the most popular pages on the site and dive in.